A state diagram is a model of a reactive system. The model defines a finite set of states and behaviors and how the system transitions from one state to another when certain conditions are true.

State diagrams are used to model complex logic in dynamic systems, from automatic transmissions to robotic systems to mobile phones. Examples of this complex logic include:

• Scheduling a sequence of tasks or steps for a system
• Defining fault detection, isolation, and recovery logic
• Supervising how to switch between different modes of operation

Building upon traditional finite state machines, state diagrams provide additional capabilities including:

• Modeling hierarchical states for large-scale systems
• Adding flow graphs to define complex decision logic
• Defining orthogonal states to represent systems with parallelism

For more information on modeling state diagrams, including these advanced techniques, see Stateflow^® and Simulink^®.